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Frequency distribution of IOP
Author(s) -
Davanger Martin,
Ringvold Amund,
Blika Sigmund,
Elsås Tor
Publication year - 1991
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1991.tb04839.x
Subject(s) - ophthalmology , glaucoma , distribution (mathematics) , medicine , normal distribution , mathematics , population , statistics , mathematical analysis , environmental health
The results of a population‐based (age ≥ 65 years) examination of the frequency distribution of IOP are reported. 3726 eyes in 1887 individuals were included in the examination. By consistent use of conventional, well‐defined criteria, glaucoma was diagnosed in 6.4% of the individual eyes. In the total material, the average IOP was 18.0 mmHg. Average IOP was 28.7 mmHg in eyes with glauoomatous damage, vs 17.2 mmHg in the normal eyes. Variance of IOP was much higher in the glaucoma group as compared with the normal group. The IOP frequency distribution curve did not fit with a Gaussian curve; it was asymmetric, skewed to the right. The distribution curve obtained by plotting the recorded frequencies was disturbed by irrelevant irregularities, both random and systematic. The irregularities could be evened out by the application of regression analysis, using the equation for the gamma distribution. The IOP frequency distribution is well represented by a gamma distribution curve. The fit is improved by excluding eyes with extremely high and low IOP.